The detection of neutrons, gamma rays and alpha particles is of great importance in the global war against weapons of mass destruction and terrorism, and in the fields of physics and engineering. Conventionally, gamma ray and alpha particle detection is performed using HPGe/NaI scintillation systems or by use of other systems that cause gas ionization to take place under high voltages, as in a Geiger-Muller (G-M) tube. The detection of neutrons is more difficult, especially in a high gamma ray background and is usually performed in liquid-scintillation (LS), He-3 or BF3 type detectors in combination with accompanying components which permit discrimination of neutrons from gamma fields. Such systems, however, are expensive and require good knowledge of nuclear physics/instrumentation, and are usually non-portable.
Specifically, conventional detectors for nuclear particle detection (especially ones that can also detect and discriminate neutrons) depend on the use of systems such as plastic scintillators, liquid scintillators to fission chambers, G-M type counters and superheated droplet detectors (SDDs). These devices (with the exception of the SDDs) require extensive electronics in the form of high-voltage power supplies, photomultiplier tubes, preamplifiers, associated pulse shape discrimination and counting logic systems. These systems rely on nuclear interactions that result in ionization, light production and amplification, etc. Note that these conventional systems are not implemented as a comprehensive hand-portable system that can distinguish neutrons from alpha particles and gamma ray sources with the benefits of low-cost, high efficiency and simplicity of operation. Also, once the SDD droplets are vaporized the droplets need to be visually inspected (or counted in a special counter) and the system needs to be taken off service and refilled or reset overnight since it is not regenerative.